Decreased likelihood of response to cardiac resynchronization in patients with severe heart failure

We hypothesized that a very advanced stage of dilated cardiomyopathy is associated with lower response to cardiac resynchronization therapy (CRT).

A consecutive cohort of 147 patients was studied before device implantation and at 12 months follow-up. All patients were in NYHA functional class III-IV and had left-ventricular (LV) systolic dysfunction (LV ejection fraction 24 +/- 7%) and a wide QRS (171 +/- 29 ms). A patient who was alive without heart transplantation and had improved by at least 10% in the 6 min walking test at 12 months follow-up was considered a clinical responder. Fifty-four patients (36%) did not respond to CRT (15 cardiac deaths, 4 heart transplantations). Quality of life indicators (>41 points), LV end-diastolic volumes (>200 mL) and mitral regurgitant orifice area (>16 mm(2)) at baseline were independent predictors of response to CRT. Patients were assigned 1 point for each predictive parameter. Patients with higher scores showed a significantly higher likelihood of non-response to CRT (chi(2) = 12 891, P = 0.005).

The results show that non-responder patients have a more advanced stage of the disease, which suggests that CRT should be indicated earlier in the disease process.